Compressor and gas cylinder containment and cooling apparatus

ABSTRACT

A fragmentation containment charging unit for gas cylinders that includes a steel housing having an interior compartment at least a portion of which defines a cooling chamber in which a compressor for use in charging the gas cylinders is mounted so as to be directly immersed so as to be in heat exchange with a cooing liquid within the cooling chamber and wherein the gas cylinders may also cooled during charging.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is related to and claims the benefit of U.S.Provisional Patent Application Ser. No. 60/611,740, filed Sep. 22, 2004,in the name of the same inventor.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is directed to protective housings or containment shieldsor enclosures for compressors of the type used to fill SCBA and scubagas tanks or containers with high pressure gases wherein the tanks orcontainers being filled are also safely supported within the containmentenclosures during filling. The enclosures house not only the compressorsbut all motors, drive assemblies, tubing, valves and the like that areused in the refilling of gas cylinders and also provide for theefficient cooling of the compressors in liquid baths created there in.The cooled compressor contained or housed with the containmentenclosures may also be used to fill exotic high pressure tanks thatcannot be placed within the containment enclosures, such as highpressure hydrogen gas tanks currently used with some automotivevehicles.

2. Brief Discussion of the Related Art

Portable air bottles or breathing air cylinders are used by scubadivers, fire fighters, rescue workers and others working or operating inenvironments where safe breathable air is not available. The bottles orcylinders are charged with a breathable gas mixture at high pressuresthat vary depending upon the type of cylinder being used. Cylinders usedby divers are often filled to pressures up to approximately 3000 poundsper square inch (psi). Due to the extreme heat build up that occurs assuch cylinders are being filled or charged, the cylinders are cooledeither by emersion in a liquid such as water or by being sprayed withthe cooling liquid. The cylinders used by fire fighters and rescuepersonnel are often filled to higher pressures, such as up toapproximately 4500 to 6000 psi, in a dry environment but using differentfilling or charging procedures.

Because of the high charging pressures associated with breathing aircylinders, there is always a risk of explosion caused by a rupture orfailure of cylinder walls and valves associated there with. Such risksare often greater when cylinders are being charged thus placingindividuals at filling or charging locations in positions where they maysubject to severe bodily harm or injury. In view of the foregoing,special containment enclosures have been designed and developed to houseair breathing cylinders as they are being filled or charged.

An example of such a containment enclosure is described in U.S. Pat. No.5,404,921 to Lamoreaux et al. This patent describes a housingconstructed out of steel having a minimum wall thickness of one-quarterinch. The housing is designed to retain two cylinders therein as thecylinders are being filled by a compressor that is also completelysupported within the housing. In this manner, both the air cylinders andthe compressor are contained within the housing as a safety precautionin the event of an explosion caused by a defect in a cylinder or acompressor component or brought about due to over heating of a cylinderor compressor components. Although the charging apparatus disclosed inthis patent provides for containment of the compressor and air cylindersduring charging, there is no provision made or suggested of cooling thecompressor or air cylinders within the containment apparatus or housing.

In view of the foregoing, there is a continued need to improve uponcontainment devices used for housing compressor components, powersupplies and air cylinders for charging or refilling such breathable aircylinders to reduce risks of possible explosions by providing moreeffective heat transfer or cooling of both the charging equipment andthe air cylinders.

In addition to the foregoing, with the increasing use of high pressuregasses used for other purposes, such as hydrogen gasses used to powerautomotive vehicles, there is also an increased need to provide for thesafe charging or filling of tanks used in such vehicles. There is asignificant increase in compressor operating temperatures when fillingthe higher pressure exotic gasses such as hydrogen that may have fillingpressures up to approximately 10,000 psi. As the temperatures increasenot only is there an increased risk of possible explosion but the damageto compressor components is also increased.

SUMMARY OF THE INVENTION

Fragmentation containment enclosures and charging units are disclosedfor compressed gas cylinders including those used by scuba divers, firefighters, rescue personnel and others wherein each unit includes anouter steel housing that encloses therein a compressor, power motor anddrive assembly for the compressor, charging lines and valves to connectthe compressor to gas cylinders or bottles to be filled or charged andwhich bottles or cylinders are preferably supported within the unitsduring charging.

In preferred embodiments of the invention, the units are movably mountedon castors or support wheels so as to be easily manipulated and moved asnecessary. At least one internal support is accessible through at leastone opening in the steel housing to retain an air or gas cylinder beingcharged. In preferred embodiments, two or more such supports areprovided within each unit. In addition, sprayers are mounted within theunit to discharge a cooling liquid, such as water, on the cylinders asthey are being charged. In some embodiments, as opposed to beingsprayed, the cylinders may be at least partially immersed in a coolingor heat exchange liquid during charging.

The compressor and cooling coils associated therewith are mounted withina compartment that is preferably water tight and separated from an areawhere the power motor and drive assembly are positioned and also spacedfrom the gas cylinder support or supports. During use of the compressorto charge gas cylinders, a liquid, that may be water or another heatexchange liquid, is circulated through the compressor compartment tothereby provide maximum cooling to the compressor and associated coilsand filters. The compressor includes or is provided with cooling or heatexchange coils that extend between the outlets of the first and secondstages of the compressor to the inlets of the second and third stagesand between the outlet of the third stage to the inlet of anpurification cylinder from which air is supplied to the gas cylindersbeing charged. Such heat exchange coils are used to cool the highpressure gasses as the gasses are compressed such that the overalloperating temperature of the compressed gasses are maintained as closeto 100° F. as is possible. The cooling of the gasses also reduces heatbuild up within the compressor.

In a preferred embodiment, an inlet connection is provided through thesteel housing of each unit to which a circulation fluid conduit may beselectively secured, such as a hose connected to a source of cool watersupply. The heat exchange liquid being circulated within the compressorcompartment may be allowed to simply exhaust from the compartment as newliquid is being introduced, or a heat exchange circuit or chiller may becreated outside the containment unit to cool the heat exchange liquidbefore re-circulating the liquid into the compartment.

A dividing wall separates the compressor compartment from a dry spacethat includes a mounting surface for a motor that may be electrically orotherwise powered to move a drive connection between the motor and acrankshaft of the compressor. In the embodiment described, the driveconnection is a drive belt that is driven by a drive pulley connected toan output shaft of the motor and a driven pulley or flywheel connectedto the compressor crankshaft.

Each containment unit also includes supply pressure gauges and well asmotor controls and temperature gauges to reflect and control thecharging of the gas cylinders when the units are in use.

It is a primary object of the present invention to provide afragmentation containment enclosure and gas cylinder charging or fillingapparatus that safely houses a high pressure compressor used to chargegas filled cylinders as well as the cylinders being charged such that,should an explosion occur, all debris or fragments will be contained,thus making the charging of gas cylinders more safe, and wherein thecompressor and related high pressure lines are bathed in a cooling orheat exchange liquid during use.

It is a further object of the invention to provide a fragmentationcontainment apparatus for charging or filling gas cylinders wherein thecylinders are continuously cooled by spraying or partial emersion in aheat exchange liquid as they are being filled.

It is yet another object of the invention to provide a containment unitfor charging gas cylinders wherein the unit is designed to be mobile tofurther facilitate its use.

It is another object of the present invention to provide a high pressurecompressor system and an enclosure or containment unit therefore whereinthe compressor and related components and cooling coils are cooled byemersion in a cooling liquid such that the operating temperatures aremaintain lower than possible using conventional cooled compressors sothat the compressors of the present invention may be use to charge moreexotic high pressure gasses such as hydrogen gasses used in automotivevehicles wherein the tanks being charged or filled cannot be placedwithin the containment housing of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the invention will be had with reference tothe accompanying drawing figures wherein:

FIG. 1 is a cross sectional view taken through a fragmentationcontainment gas cylinder charging unit of the invention illustrating acompressor immersed within a cooling liquid;

FIG. 2 is a rear elevation view, partially in cross section, having someof the motor and gauge components removed for clarity of the unit shownin FIG. 1;

FIG. 3 is a cross section taken along line 3-3 of FIG. 1 on a reducedscale and with the compressor and other components removed for purposesof clarity;

FIG. 4 is a front perspective view of a modified containment housing forthe charging compressor and related components of the invention;

FIG. 5 is a rear perspective view of the modified containment housing ofFIG. 4; and

FIG. 6 is a perspective view of a conventional scuba gas cylinder of atype that may be filled or charged using the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With continued reference to the drawings, a fragmentation containmentunit 10 for charging or filling one or more gas bottles, cylinders ortanks 12, see FIG. 6., is shown. The cylinders may include the type usedby scuba divers, fire fighters, rescue workers and the like that are ofa size to be carried or worn during use. As previously described, suchcylinders may be initially charge with gas pressures up to 4500 to 6000psi using conventional air or gas compressors such as shown at 14.

The containment unit 10 includes a housing 15 constructed of at leastthree sixteenth of an inch thick steel plate and have opposite sidewalls 16 and 17, front and rear walls 18 and 19 and bottom wall 20.Preferably, the front and opposite side walls are formed of a singlepiece of material bent or formed into a u-shaped configuration thatmates with an L-shaped piece that forms the rear and bottom walls. Thesetwo pieces are welded along their common joint areas such that thehousing is generally sealed, except as will be described in greaterdetail herein. In at least one embodiment, a removable top 22, alsoformed of the steel material or of a steel mesh material, is adapted tobe locked or otherwise secured in covering relationship with respect toand interior compartment 24 defined by the housing. The top is designedto be removed to permit ease of access to the compressor and othercomponents mounted within the compartment and, in some embodiments, maybe connected by hinges to one of the walls to facilitate opening.

With particular reference to FIGS. 1-3, the lower portion of thecompartment 24 is divided by an interior wall or baffle 25 such that afirst cooling chamber 26 of the compartment may be used to contain aliquid, such as water, that may be circulated therein, while a separatedry portion 27 is also provided within the compartment. A water orcooling bath is designated by “W” in the drawings. The water or otherliquid is used for cooling the compressor 14 which is securely mountedwithin the cooling chamber 26 of the compartment 24 so as to be fullyimmersed within the cooling liquid. This direct emersion cooling of thecompressor will not only prolong the life of the compressor by reducingdamage to components of the compressor generally directly related to theheat build up within the compression cylinders of the compressor butwill also reduce the risk of compressor explosion during charging of thegas cylinders within the containment unit 10.

A liquid inlet 28 is provided in the rear wall of the housing and acontrol valve 29 to regulate or stop liquid flow into the coolingchamber 26 may be mounted in communication with the inlet. Although aheat exchange circuit may be connected to the liquid inlet 28, in mostembodiments, the inlet will include a threaded male nipple or connector30 for cooperatively receiving a female connector associated with aconvention garden or industrial type hose, not shown. A liquid exhaustoutlet 31 is also provided in the rear wall of the housing. The outletmay also be provided with a control valve 32 to adjust the rate ofliquid flow from the cooling chamber 26 of the compartment 24. If thecontainment unit is being used with a liquid cooling or heat exchangecircuit that would permit the cooling liquid to be recycled in a closedcircuit to the cooling chamber, appropriate valves to control fluid flowrates and pressures would have to be provided. When a continuous sourceof cooling liquid is provided, a conventional hose may also be connectedto the outlet to permit overflow liquid to be conveyed from thecontainment unit.

In some embodiments of the invention, a circulation pump or paddle 33driven by an electric motor 34 may be provided within the coolingchamber 26 to circulate the liquid therein to ensure a more uniform oreven heat exchange between the cooling medium and the compressor. Thepump receives power from a power cord, not shown, that is connected toan electric motor 35 that is mounted to a bracket 36 secured within anupper portion of the compartment 24.

The motor 35 includes an output drive shaft 37 that is connected to adrive pulley 38. A drive belt or chain 39 extends between the drivepulley and a driven pulley or flywheel 40 connected to an input shaft 41associated with a crankshaft (not shown) of the compressor 14. It shouldbe noted that the input shaft 41 extends through a liquid proof bearingthat is mounted through the interior wall or baffle 25 so that there isno leakage of liquid from the cooling chamber 26. For safetyprecautions, a belt or chain shield, not shown, is provided within thedry portion of the chamber to prevent accidental contact with the drivebelt or chain. Due to the size of the flywheel 40, a portion of theflywheel may have to extend through an opening 45 formed in the lowerwall of the housing as is shown in FIG. 1. The opening 45 is enclosed bya cover 46 made of the same steel material as the walls of the housing.

The containment unit 10 shown in the drawings may be approximately 4feet in height and width and approximately 3 feet in depth between thefront and rear walls. If the unit is enlarged, the flywheel may be fullycontained within the housing without the cover 46 being required. Also,the preferred embodiment of the invention is designed to the easilymanipulated and, in this respect, may include castors or wheels 50 forsupporting the housing.

Although the containment unit 10 may be modified to allow any number ofgas cylinders to be charged therein, in the embodiment shown, there aretwo cylinder supports or cylindrical cradles 52 mounted with the housingon which a pair of gas cylinders 12 may be supported during charging.The cylinder supports are generally aligned with a pair of spacedopenings 54 provided in the front wall 18 of the housing. The openings54 May be selectively covered with pivotal covers 55 formed of the samesteel material. The covers 55 are preferably mounted within the housingand are attached to piston members, not shown. The pistons permit thecovers to open inwardly into the housing like doors as the gas cylindersare inserted through the openings 54. After the gas cylinders are restedon the supports 52, the pistons will automatically move the covers 55 totheir closed positions as shown in FIG. 4.

Mounted with the chamber 24 adjacent the gas cylinder supports 52 aresprayers 56. The sprayers are mounted and oriented so as to bathe thegas cylinders 12 within the compartment 24 with cooling liquid as theyare being charged by the compressor 14. The sprayers are connected to acommon header 57 that extends through a control valve 58 to a connector59 to which a conventional hose or other coolant supply line may beselectively connected. If the cooling liquid being sprayed is the sameas the cooling liquid in the cooling chamber, the cooling spray ismerely allowed to pass into the cooling chamber to be discharged withthe liquid passing there through. If a different coolant is being used,separate collection plates would be positioned below the cylindersupports 52 that would channel the sprayed coolant to a point ofdischarge. As shown in the drawings, separate control valves 60 and 61may be provided to control the amount of coolant flow through each ofthe sprayers 56. Using the invention, when dry charging or filling ofsome type of gas cylinders is being done using the invention, thesprayers 56 are not used. It should be noted that is only one gascylinder is being charged that requires cooling, only one of the valves60 and 61 would be opened to permit flow.

As opposed to spraying the gas cylinders with coolant, the gas cylindersmay be mounted within the housing of the containment unit so that asubstantial portion of each cylinder extends into the cooling chamber 26to thereby be cooled by immersion within the liquid circulating therein.

In addition to cooling the compressor as previously described, thecompressor and the gas being compressed thereby are further cooled usingthree sets of cooling coils 62, 63 and 64 that connect the variouscompression cylinders or stages of the compressor, as is shown inFIG. 1. The compressor shown includes three compression cylinders 65, 66and 67. With the present invention, gas within the low pressure cylinderor stage 65 exits there from into cooling coil 62 wherein the gas isconveyed in heat exchange relationship with the cooling liquid in thechamber 46. The compressed air pressure entering the inlet to the secondstage or compression cylinder 66 of the compressor 14 is reflected bygauge 70 that is viewable through the front wall of the housing. The airbeing compressed in the initial stage is received through an inlet line68 that extends form an air inlet filter 69.

In the second stage or compression chamber 66, the air is furthercompressed and discharged into cooling coil 63 that conveys the furthercompressed gas to the inlet of the third stage high pressure compressioncylinder 67. Pressure of the gas leaving the second stage is reflectedby gauge 71. In the third stage, the compressor is compressed to thedesired end pressure that may be up to 6000 psi for breathing gascylinders or as high as 10,000 psi for exotic gas uses such as forfilling hydrogen tanks in automotive vehicles.

The compressed gas from the third stage is cooled by passing throughcoil 64 and is conveyed to a filter tank 72 wherein the high pressuregas is filtered before being passed through charging valves 75 and 76 tothe charging lines 77 and 78, respectively that are used to fill orcharge the cylinders 12 carried within the supports 52. The pressure ofthe third stage gas is reflected on the filling pressure gauges 80 and81. The cooling coils 62-64 may be, for example, formed of a length oftwenty or more feet of metal tubing. The tubing dimensions will becontrolled or dictated by the pressure of the gasses that are to flowthere through.

When pressure within the compressor system exceed a pre-determinedpressure and the compressor is shut OFF automatically, pop-off valves82, 83 and 84 will automatically open to relieve system pressure.Further, is the compressor temperature elevates over a pre-determinedtemperature, such as 130° to 140° F., the compressor will automaticallyshut down and the pop-off valves will open. The temperature of thecompressor is reflected on a gauge 86. The rate of the cooling liquidflow through the cooling chamber may have to be adjusted in the eventthe temperature raises over 90° to 100° F. Generally, it is preferred tooperate the system at as close to 90° F. as possible, and suchtemperatures are possible using the bath or emersion cooling techniquesdescribed with respect to the present invention.

It should be noted that each of the fill or charging valves 75 and 76are controlled using manual valve controllers 92 and 93, respectively.Manual draining of the compression cylinders of the compressor 14 arethrough controllers 94, 95 and 96. Controller 94 controls a dump valve97 for relieving pressure in the first stage, controller 95 controls adump or drain valve 98 for relieving pressure in the second stage andcontroller 96 controls dump or drain valve 99 for relieving pressure inthe third stage.

A conventional oil accumulator 88 is also mounted within the housing andis associated with the compressor 14 in a normal manner. To dump thecooling liquid from the chamber 26, a drain valve 90 is mounted to therear of the housing.

To further control operation of the containment and charging unit 10,various gauges as well as ON/OFF switches for the motor are provided ina control box 100. The OFF switches will include an emergency shut downswitch. Although not shown, automatic motor cut-off switches are provideto stop gas cylinder charging when predetermined charging pressures arereached in order to prevent over charging and any chance of accident dueto over charging.

With specific reference to FIGS. 4 and 5, the containment housing 15 maybe formed having a pivotally mounted open mesh steel cover 102 asopposed to the top 22. In this embodiment, the rear wall 19 may onlyextend upwardly to a height above the interior baffle or wall 25 of thehousing or slightly above the cylinder supports 52 with the cover 102being L-shaped and connected by hinges 104 to the upper edge 106 of therear wall. An appropriate handle 105 may be provided on the cover.

1. A fragmentation containment gas cylinder charging apparatuscomprising a housing defining an enclosed compartment, means forsupporting at least one gas cylinder within said compartment, a least aportion of said compartment defining a cooling chamber in which acooling liquid may be circulated, a charging compressor mounted withinsaid cooling chamber so as to be in direct heat exchange with a coolingliquid circulated therein, means for introducing the cooling liquid intosaid cooling chamber and means for discharging the cooling liquid fromsaid cooling chamber, charging lines extending from said compressor tosaid at least one gas cylinder, and means for selectively cooling saidat least one gas cylinder within said compartment as the at least onegas cylinder is being charged.
 2. The charging apparatus of claim 1wherein said means for cooling said at least one gas cylinder includesat least one sprayer for spraying a cooling liquid onto said at leastone gas cylinder.
 3. The charging apparatus of claim 1 wherein saidmeans for cooling said at least one gas cylinder includes means forsupporting said at least one gas cylinder so as to be at least partiallyimmersed within cooling liquid within said cooling chamber.
 4. Thecharging apparatus of claim 1 wherein said housing is formed of at leastthree-sixteenth inch steel.
 5. The charging apparatus of claim 1including means for circulating said cooling liquid within said coolingchamber.
 6. The charging apparatus of claim 1 including an internalbarrier for separating said cooling chamber from a dry portion of saidcompartment, a motor mounted within said dry portion and means forconnecting said motor to a drive input into said compressor.
 7. Thecharging apparatus of claim 6 including means for supporting at leasttwo gas cylinders within said housing.
 8. The charging apparatus ofclaim 7 including wheel means for movably supporting said housing. 9.The charging apparatus of claim 1 wherein said compressor includesmultiple compression stage cylinders, cooling coils connected betweeneach of said compression stage cylinders, and each of said cooling coilsbeing immersed with cooling liquid within said cooling chamber.
 10. Thecharging apparatus of claim 9 including a filter at least partiallyimmersed in said cooling chamber through which compressed gas from saidcompressor must pass to the gas cylinders being charged.
 11. Thecharging apparatus of claim 9 including a gas inlet line extendingthrough said cooling chamber to a first compression stage cylinder ofsaid compressor.
 12. A fragmentation containment gas cylinder chargingapparatus comprising a housing defining an enclosed compartment, a leasta portion of said compartment defining a cooling chamber in which acooling liquid may be circulated, a charging compressor mounted withinsaid cooling chamber so as to be immersed in direct heat exchange with acooling liquid circulated therein, means for introducing the coolingliquid into said cooling chamber and means for discharging the coolingliquid from said cooling chamber, and charging lines extending from saidcompressor to connect to the at least one gas cylinder.
 13. A method ofsafely charging gas cylinders with high pressure gas using a compressorwherein the compressor is selectively connected to the gas cylinders inorder to introduce pressurized gas therein, the method including thesteps of immersing the compressor in a cooling liquid during charging ofthe gas cylinders.
 14. The method of claim 12 including the additionalstep of cooling the gas cylinders with cooling liquid during charging.15. The method of claim 13 wherein the compressor is a multiple stagecompressor including the additional step of cooling compressed airexiting one of the stages of the compressor by emersion within thecooling liquid before introducing the compressed air into the nextcompression stage.